Latham had an 8-point lead over his Democratic opponent with 93 percent of precincts reporting in the southwestern Iowa district, according to the Associated Press.

A top ally of Speaker John Boehner (R-Ohio), Latham raised considerably more money than Boswell did. But the Democrat had a geographical advantage in this Tossup race, with more of his old district included in the new one.

Boswell's defeat marks the first Member to lose to a colleague tonight.

In Ohio, Rep. Jim Renacci (R) leads Rep. Betty Sutton (D) in the 16th district by a slim 4-point margin, but with only 57 percent of precincts reporting. The Associated Press has not called that race yet.